For most people, buying a new sustainable roofing solution is one of the most important and expensive maintenance decisions for their biggest investment. For many homeowners, the cheapest option is always the default choice while others choose a style they like and leave the details to a contractor.
It’s not always easy to find out who makes your roofing material. It can be even harder to find out if they recycle or work to minimize their environmental impact. But the impact of our roofing choices, both on our homes and on the environment, is too great to ignore.
We’ve researched roofing materials and manufacturers to make buying an eco-friendly roof easier. Our results are far from comprehensive, but as more consumers begin to demand this information, more manufacturers will begin to provide it. When they do, we’ll update our results.
In this article, we consider the merits of the most common manufactured roofing materials. Natural roofing materials are not manufactured, so they are not included in the comparison chart.
Asphalt is the cheapest option. It is so common that many people assume you are talking about asphalt shingles when you talk about sustainable roofing.
Laminate shingles (also called architectural or dimensional) are fiberglass layered between asphalt and ceramic granules. They can be made to look like more expensive materials, such as tile, wood, and slate. Although slightly more expensive than basic three-tab asphalt shingles, laminate shingles perform better. Single-plane shingle roofs (also called 3-tab) are the easiest roof to retrofit with a solar panel system. Several asphalt tile manufacturers even offer solar-integrated asphalt roofs.
Asphalt roofs usually last 20 to 25 years, but some newer, high-quality products will last 40 years or more. Although technically recyclable, most asphalt roof shingles end up in the landfill.
Wood Shingle and Shake
Prized for their natural look, handmade shakes have earned their reputation for being expensive, but machine-made wooden shingles do not cost much more than asphalt. Wood shingles can mold, split, or rot in wet climates.
Untreated wood shakes are unrated for fire safety and therefore are not permitted by building codes in many areas prone to wildfires. Fire retardants can help wood shingles and shakes achieve a Class B fire rating. Including additional materials in the roof assembly can help them meet a Class A rating. However, composters will not accept chemically treated shingles. Despite these vulnerabilities, wood roofs can last 25 to 30 years. Meticulous maintenance and mild climates can extend the lifespan to 50 years.
Sourcing wood shingle or shakes from a local sawmill will reduce the greenhouse gases associated with transport and ensure a regionally appropriate wood species is used. Whether sourcing locally or from a national brand, look for FSC-certified wood.
Metal roofing options include steel, aluminum, copper, and alloy strips. They come in various shapes and textures, from standing seam panels to shingles that resemble tile or slate. Metal can be more expensive than asphalt, but except for copper, it is still among the cheaper sustainable roofing options. Proper installation and good insulation are required to minimize noise from rainfall and wind “chatter.” Metal is lightweight, virtually fireproof, and particularly suited to thin-film solar power systems. Metal roofs last at least 40 years and can last as long as 75 years. They are also the most easily recycled roofing material.
Tile roofs dominate on the Mission- and Spanish-style homes of the U.S. West and Southwest. Although they are more common in desert areas, some tiles are suitable for use in cold climates. Roof tiles can be made from true terracotta clay, ceramic, or concrete. Tile roofs are very heavy and may require additional framing. Concrete is cheaper than clay but has many of the same advantages. Tile roofs last 40 to 50 years on average but have been known to last up to a century.
Slate roofs are heavy enough to require extra framing. As arguably the most expensive roofing material, they are not an option for most budgets. But they are also nearly indestructible, with a lifespan of 50 to 100 years or more. Be aware of the origin of the slate that will be used, as the sustainability and durability can vary. Because slate is so heavy, the distance slate tiles must be shipped will significantly affect not only the cost but the environmental impact of choosing this natural material.
Synthetic roofing can be made from a variety of materials, such as plastic, clay, rubber, or asphalt. And it is usually designed to resemble natural materials like slate or wood. Thermoplastic single-ply (usually used on flat or very low slope roofs) has the highest Energy Star rating of any sustainable roofing product. For homeowners interested in this material, Firestone’s brand GenTite makes it available for residential applications.
Few synthetic materials have been around long enough to gauge their long-term performance. But several demonstrate promise, with high ratings in performance tests and warranties of 50 years. A synthetic roof may be a good option for someone willing to do a lot of research, but we won’t be comparing them here.
Roofing Rating Criteria
When reviewing sustainable roofing materials and manufacturers, we considered the following criteria, including warranties and certifications.
The lifespan of your roof is largely a function of material choice. Slate roofing will last the longest, on average, and wood or 3-tab asphalt shingles have the shortest average lifespan. However, individual products can be manufactured to higher standards. So, a very good asphalt roof may last as long as an average metal one. For our comparison of manufactured roofs, we started with metal roofs ranked highest, followed by tile and then asphalt. Then we modified the manufacturers’ rankings based on warranties.
The radiative properties of sustainable roofing materials are solar reflectance and thermal emittance. Both are rated on a scale of 0 to 1, where 1 is the most reflective or emissive. The Cool Roof Rating Council and Energy Star utilize solar reflectance and thermal emittance to rate “cool roofs.” A cool roof can reduce cooling energy costs by 7-15 percent, minimize temperature fluctuations inside the home, and reduce the urban heat island effect.
Energy Star certified roof products have a solar reflectance of at least .65 for low slope roofs and .25 for high slope roofs. High solar reflectance is the most important characteristic for saving energy during warmer months. High emissivity can also help reduce cooling costs in hot climates but may not be as desirable in cold ones. Cool roofs may qualify for rebates in California and in other areas. For this comparison, we included only manufacturers that make Energy Star rated roofing materials, prioritizing those offering products with the highest solar reflectance. Note that highly rated manufacturers may still make many products that do not meet Energy Star standards.
Solar panels can be mounted to almost any roof, but manufacturers offering a solar-integrated roofing system got a boost in the ranking.
All of the sustainable roofing materials we considered are technically recyclable. However, in practice, many homeowners have trouble finding local recycling options. When ranking manufacturers, we considered their use of recycled materials and their recycling practices in production facilities.
To view our printable roofing comparison chart, click the image below.
The family-owned Malarkey Roofing lives up to the reputation of its Portland home town. They build vegetative roofs in addition to the more common asphalt tile offerings. But even their asphalt tiles have an eco-twist. Besides having the highest solar reflectance of any Energy Star asphalt shingle, Malarkey uses 3M Smog-Reducing Granules that convert smog into water-soluble ions (NO3), actively reducing air pollution. One roof has the same smog-fighting potential as planting two trees.
Their shingles contain up to 35 percent recycled material. Other environmental efforts include using recovered methane to power their Portland production facility and an emphasis on recycling production waste. All three Malarkey manufacturing facilities (Portland, Oregon; South Gate, California; Oklahoma City, Oklahoma) have achieved the Waste Diversion from Landfill certification from GreenCircle by recycling between 89 percent and 94 percent of manufacturing waste.
The Midwestern company Ludowici makes clay tiles in New Lexington, Ohio, from locally sourced materials. They offer a 75-year warranty, with an expected lifespan of a century. With both Energy Star and Cradle to Cradle certification, their most energy-efficient tiles have a solar reflectance of .79, the highest of any residential product in this comparison.
Although they only use 3 percent recycled materials in their standard product, the Ludo360 product line uses 40 percent recycled material. They claim their manufacturing process generates no waste.
California-based MCA (Maruhachi Ceramics of America, Inc.) makes true terracotta clay tiles with lead-free colors. Warrantied for 50 years and ASTM C1167-standard frost-resistant, these traditional tiles contain 60 percent recycled waste material from aggregate mining. The company incorporates some recycling into their manufacturing process, reusing glaze water and capturing heat to dry wet tiles. They sell rejected tiles for use in tennis courts and baseball fields.
MCA helps to extend the life of existing roofs by manufacturing custom replacement tiles to match historic designs. Energy Star tiles provide higher solar reflectance values than most other roofing materials. MCA clay tiles are an especially green choice for homeowners in Californian and the Western United States; those further afield should consider the added environmental impact of shipping a heavy roofing material over long distances.
Interlock Metal Roof Systems
Interlock’s variety of metal roofing systems include a solar-integrated system. With the motto, “Never re-roof again,” and a minimum warranty of 50 years, Interlock is serious about long-lasting roofs. When it is finally time to replace one, metal roofs are easily recyclable in most communities. In fact, Interlock roofing panels contain up to 95 percent recycled materials.
Although they proclaim the environmental benefits of their product, Interlock does not provide information about environmental efforts in their manufacturing processes. They are based in British Columbia, Canada, with 10 distribution centers across the continent.
CertainTeed puts sustainability right in their mission statement: “We aspire to be North America’s recognized leader in sustainable habitat.” With 60 manufacturing facilities in North America, CertainTeed probably won’t need to ship your roof long-distance to reach you. The company makes more than 300 residential roofing products. Most of these are asphalt, but they also make metal roof tiles that resemble clay tile, slate, and shake. With such a variety of products, warranties vary from 10 years to lifetime.
Products using CertainTeed’s trademarked CoolStar granule technology and the Landmark Solaris GOLD roofing product series are Energy Star certified. They also offer a solar-integrated roofing system that uses thin-film photovoltaic laminates. The company claims to recycle nearly 90 percent of the waste generated in their manufacturing facilities and to incorporate 250,000 tons of recycled material into their products every year.
US Tile is a Boral brand specializing in clay tiles with a warranty of 50 years and up to 59 percent recycled content. Their energy-efficient roof installation system saves up to 22 percent per year on home heating and cooling costs compared to the standard composition asphalt shingle roof. Despite Energy Star and Cradle to Cradle certification, their tiles do not have quite as high solar reflectance as other clay tiles. Their tiles are available nationwide, but manufacturing appears to be based in the Eastern U.S.
Eagle Roofing Products is the concrete tile division of family-owned Burlingame Industries. Concrete tiles do not have the life expectancy of natural clay but are still likely to outlive their 25-year warranty. They do match clay’s high solar reflectance value. And when installed with a sheathing ventilation system, can reduce heat transfer into the attic by almost 50 percent compared to an asphalt shingle roof.
Eagle’s standard tiles contain only 2.5 percent recycled content. Their lightweight products are made from 65 percent recycled material. Eagle does seem to be taking some eco-minded steps in its manufacturing processes, like reducing electricity usage and selecting vegetable- or water-based chemicals.
Like clay tiles, concrete tiles are heavy, which exacerbates the environmental cost of shipping. Eagle’s concrete tiles will be a greener choice for homeowners who live closer to its manufacturing facilities in California in Rialto and Stockton; Phoenix, Arizona; and Sumterville, Florida.
Berridge Manufacturing Company specializes in the research and development of architectural sheet metal products, including sustainable roofing, that they sell directly to architects and contractors. Their warranty is quite short for metal at only 20 years. But their products contain roughly one-third recycled materials and their Energy Star rated products have the highest solar reflectance of any metal roof. Their 11 manufacturing facilities are concentrated in Texas and the South, but there are a few in other locations, and metal sheets are not as carbon-intensive to ship as some other roofing materials.
Boral, the parent company to US Tile, makes a concrete tile that resembles clay, slate, or wood. They source the raw materials for the tile locally to the factory, reducing the environmental impact of transportation during manufacturing. Boral is a major source of fly ash from coal-fired power plants, so although we could not confirm it, it is likely that their concrete tiles contain recycled fly ash.
Tamko is a family-owned business and one of the largest roofing manufacturers in America. They specialize in asphalt shingle with slightly higher solar reflectance than other Energy Star rated asphalt products. They offer a limited lifetime warranty on their shingles.
You Might Also Like…
Sustainable Roofing Buyers’ Guide
April 8, 2019
Earth911 Podcast, April 5, 2019: Recycling Issues with ISRI Chief Lobbyist Billy Johnson
April 5, 2019
Earth Day Prep: Make an Earth Decade Plan
April 5, 2019